1.{3x-y=5 2.{2x/3+3y/4=1/5{5y-1=3x=5 { 5x/6-5y/2=2

{(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) （x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 1.(2x-3y)(2x+3y)=2.（5x+3y）（3y-5x）3.（x-3y）（-x+3y）=4.（x+y-z）²= 先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5 1.（x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2) 化简:5(x-y)+2(x+y)-3(x-y) (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一 1.已知:x-2y=3,求[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]除4x 的值 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1